472 
LOWER OOLITIC ROCKS OF ENGLAND : 
Uniform physical structure is more important than chemical 
composition, for the value and durability of a stone cannot be 
determined by analysis. Attention has been drawn by Mr. H. 
W. Burrows to the value of a microscopical examination of 
building-stones ; but, in reference to the oolite?, I think we cannot 
at present speak confidently on the matter, and thnt it would be 
difficult to tell a good, from an inferior, freestone, in a microscopic 
slide. 
Analyses of Inferior Oolite from Bunchy and Painswick, and of Great 
Oolite from Bath, show from 94 to nearly 98 per cent, of carbonate of lime 
and from 19 to ' 93 of silica. 
Stones that are readily dissolved by carbonated waters, exhibit in 
buildings and often in quarry-faces a lime-wash over their surfaces. The 
presence of much earthy or readily wasted matter, may be tested by C. H. 
Smith's plan of immersing small pieces of the rock in a glass of clear 
water, as the water after balf an hour will become slightly turbid. 
The weight of different Oolitic building-stones varies from about 116 to 
155 pounds per cubic foot : but it is no test of the relative durability : it 
is of importance mainly with reference to the particular work for which 
the stone is used. Again the 'Weight which any particular stone will bear 
should be ascertained if it is to be subjected to particular stresses ; but in 
an ordinary way the greatest strain is less than 16 tons to the square foot, 
and even poor freestones will bear about eight times that amount.* 
The following analyses may be useful to show the composition of 
Oolitic building-stones : 

Box. 
Ancaster. 
Ketton. 
Barnack. 
Ham 
Hill. 
Carbonate of lime 
94-52 
93 -59 
92-17 
93-40 
79-30 
Carbonate of magnesia 
2-50 
2-90 
4-10 
3-80 
5-20 
Silica - - - - 
0-0 
o-o 
o-oo 
o-oo 
4-70 
Iron, alumina - 
1-20 
0-80 
0-90 
1-30 
8-30 
Waert and loss 
1-78 
2-71 
2-83 
1-50 
2-50 
100-00 
100-00 
100-00 
100-00 
100-00 
Traces of bitumen were noticed in all these analyses. Another analysis 
of Bath stone showed '50 per cent, of silica. Traces of sulphate of lime 
and phosphoric acid have been observed in some Oolitic freestones.f 
The following statistics show the density and absorbent powers of some 
of the rocks : 
* See remarks in Notes on Building Construction, Part 3, ed. 2, p. 6 ; C. H. 
Smith, Lithology, Journ, K. Inst. Brit. Archit. 1840, p. 167; papers by G. F. Harris, 
in the " Builder " for 1886 ; and H. W. Burrows, Journ. K. Inst. Brit. Archit. ser. 2, 
vol. ix. p. 284. 
t See Analyses by Prof. Daniell, in Report on the Selection of Stone for the New 
Houses of Parliament ; Mem. Geol. Survey, vol. ii., part 2, p. 690 ; A. Voelcker, 
Journ. Bath and W. of Eng. Soc., ser. 2, vol. vi. p. 64 ; and Builder, vol. lix. p. 324. 
